Telescoping seating systems are well-known in the art, and they generally include a plurality of rows, each row having wheeled carriages for movement along the floor of a gymnasium, or auditorium, a frame or understructure including columns or posts extending upwardly from the carriages to the height of a given row, and a riser beam mounted horizontally to the tops of the columns. A deck, including a foot rest platform and seating is cantilevered from the riser beam and columns by means of arms secured to the riser beam.
One of the primary problems facing engineers designing telescoping seating systems is to provide seating which is comfortable and secure in the use position, yet which conveniently folds and is stored in the space between adjacent rows in the storage position. If the seating is simply wooden benches, then the height of the bench can be less than the vertical space between decks when adjacent rows are nested for storage, and the problem is obviated. However, bleacher-type seating is generally considered to be less comfortable to an occupant than individual chairs. Individual chairs, however, provided with a seat and back as well as arm rests obviously cannot fit in the space between adjacent decks for storage, since that space typically is in the range of 10-12 inches.
Thus, individual chair seating is preferred over bleacher seating in terms of convenience and comfort. However, if the seating requires manual labor to raise and lower the chairs, it can be a significant disadvantage because, depending upon the size of the arena, it can require a substantial number of workers who are not ordinarily employed on a continual basis just for this task.
Therefore, attempts have been made to provide individual chair seating which is raised and lowered automatically with the extension and retraction of the rows. One such system is disclosed in the Van Ryn U.S. Pat. No. 4,063,392. In this system, the seats of the chairs are permanently mounted to the forward portion of a deck and only the back of an individual chair is raised or lowered. The back is locked in the raised position and it is released in response to the actuation of a single tube mounted beneath the deck and extending along the width of the deck beneath the seating. Separate latching mechanisms are provided for each chair back, and all the latches are released in unison by the actuator tube. The backs are raised to the use position by means of a spring.
Another automatic chair platform system is disclosed in the Hartman U.S. Pat. No. 4,155,202. This system provides for the convenience and comfort of individual chair seating wherein the height of the seat is independent of the rise of the system. A number of chairs are grouped together, and each gang of chairs is locked in place by at least two latching members which are engaged by the nose portion of the next higher row in order to unlock the seating. This system had the disadvantage that it is susceptible to problems when rows become out of parallel.
That is, during the retraction of a row, if one side of the row wheel carriage engages an obstruction, the row being retracted may become slightly out of parallel, thereby rendering it uncertain as to whether both latches would be disengaged prior to having a portion of the seating engage the nose of the next higher row. In this system, torsion rods are connected between the seating and the deck for supplying a counter-balancing force to the seating when it is lowered, to at least partially offset the weight of the seating when it is raised to the use position. In order to raise the seating, members were hinged to a higher row to engage the seating on the next lower row so that when the lower row is extended, the hinge members engage the seating and assist the torsion springs in elevating it.
Another automatic seating system, and one which was made commercially available, is disclosed in U.S. Pat. No. 4,446,659. This system has a single drive rod for locking and unlocking individual chairs, but due to manufacturing tolerances in a structure of this type, once the drive rod locked any one of the chairs in a row, it becomes fixed and can not tighten the latches of adjacent chairs so that some of the chairs are permitted a slight movement which, though not unsafe, may give a feeling of looseness to an occupant. Further, when it is desired to provide arm rests on a chair, the length of the arm rests are limited by the available space for storage because the arm rests are fixed to the chair frame.